The eco-price: How environmental emergy equates to currency

Energy flows through economies in a hierarchical pattern with vast amounts supporting the base while each step has less and less flowing through it. Money is inextricably connected to many of these energy flows in a countercurrent. At the most aggregated scale of an economy, where its gross domestic product is measured, the mean ratio between the flows of solar emergy and money is known as the emergy-to-dollar ratio (EDR). However, the relationship between solar emergy and money is not constant along the energy hierarchy of an economy. While estimates of this dynamic relationship exist for marketed goods and services, there has been less work to estimate the relationship for nonmarketed services. We develop the “eco-price” to meet the goal of better predicting correlation between environmentally derived services and currency. It is defined as the flow of emergy of an ecosystem service relative to the money estimated to flow as a countercurrent. Twenty-nine eco-prices were estimated from cases of known exchange for water, soil, air pollution and natural resource commodities. The eco-price reconciles the biophysical value of the environment with economic value and extends the capability of emergy analysis to suggest “marketable” monetary values for the work of the environment.